Pneumatic drilling apparatus



Filed May 2l, 1946 2 SHEETS-Sl-EET 2 ATTORNEYS Patented July 8, 1952 yUNITI-:D STATES PNEUMArIo DarLLrNG APPARATUS August H. Katterjohn, Houston, Texi, assignor to Reed Roller Bit Company, HoustomTex., a cora poration of Texas Application May 21, 1946, Serial-No.1 671,195 i This invention relates to pneumatic drilling tools customarily known as rock drills and has for its general object the provision of such a tool in which the expense involved in replacements necessitated by wear, in the driving connections will be minimized, and in which better provision will be made forblowing through thedrill steel.

In previous structures attempts have been made to reduce the expense of replacements due to wear, with particular emphasis directed toward avoiding the necessity for the replacement of large and expensive parts such as the main working cylinder casting. These attempts in the past have for the most part taken the form of replaceable portions which might be termed liners, inserted in the ends of the cylinder castings and in the interiorsof the members ordinarily disposed in splined engagement with the driving pistons for the transmissionk of rotary movement from these pistons to the drill steels.

Such arrangements, however, 'were expensive in that a larger number of parts was required and their only effect wasto reducethe sizes of the parts requiring replacement. The'irequency of replacement was not reduced 'nor was replacement facilitated. On the contrary, replacement was many times more difcult because of the necessity of removing the liners or inserts from the parts in which they were mounted. Furthermore, the members thus inserted for splined engagement with the driving pistons kfor'transmitting rotary motion therefrom were in some cases threadedly mounted in the members in which they were placed, and were subject to coming loose in some cases, becoming so tight in other casesthat they lcould not be removed, and instill other cases becoming so tight that they induced breakage inthe parts in which they' were' mounted.

Provision for blowing air through the drill steel in such previous constructions has taken rthfe form of passages drilled longitudinally through the wall of the cylinder casting to a point beyond the driving sleeve or has taken the form of passages drilled through the driving sleeve longitudinally, or loose fits between the driving 'sleeve and the cylinder casting. ln the case of passagesdrilled through the walls ofthe cylinder casting or through the driving sleeve rlongitudi-- nally these, parts had to be made thicker in order yto provide adequate strength and this was objectionable.v This was particularly true in the case of composite driving sleeves made upof a steel shell with a softer metal insert threaded into it because in such sleeves the Steel shell was 5 claims. (ci. 'm1- 7)` stressed longtiudinally inoperation. The use of .poor iits between the driving sleeve and the cylinder casting has proved unsatisfactory in that it does not allow the passage of4 a suicient amount ofy air, and the loose fit is objectionable as such.

A more specific object of this invention therefore is to provide a structure of the type referred to in which the number of parts requiring re-g placement due to wear occasionedby the transmission of rotary movement from the piston to the drill bit will be reducedV to a minimum.

Another object of this-invention is to provide a structure of' the type referred to in which substantially-all of the Wear occasioned Vby the transmission of such rotary movement will be taken on one readily replaceablel element. a i- Another object of this .invention is to provide a single transmission element Vwhich will take a major portion of Wear occasioned by the transmission of rotary movement from the piston lto the drill bit, and which will be relatively cheap and easy to manufacture and easy to replace.

Another object of this invention is to provide a means/for transmitting rotary movement from the piston to the drill bit by which the interruptions due to breakage will be reduced toa minimumand the time and expense of replace'- ments dueto wear will likewise be reduced to a minimum. y l

Another object of this invention is to provide an arrangement for transmitting rotary movement from the piston to the drill bit in such a structure, by which arrangement `the parts will be maintained inxmore perfect alignment than the previous arrangements. y

' A further object of this inventiongis to provide a single readilyA replaceable element for the transvmission Vof rotary movement'from the=pistonto thev drill bit, which element may be accurately fitted to all the :parts With which it cooperates and yet which is capable. of providing rfor the Apassage of large amounts of blowingair from its Referring more in detau to the drawing, theV invention is illustrated as embodied .in a rock drill having a cylinder member `or .casting i 4with a power cylinder 2 formed therein and a hammer or driving piston 3 whichreciprocates within the cylinder. The rear end of the cylinder 2 is closed in the customary manner by the ,back head 4 which has a manually controlled throttle valve 5 Amounted. thereon for the purpose of controlling t-he ingress .of live air through the vhose 16 from Vthe .source of supply. This lvalve :has `a fhandle -which vas illustrated :may occupy anyone of three positionsJ the lower position which is shown in solid lines in Fig. 2 being the position occupied by the -valve handle for normal running .of 'the drill, .the intermediate dotted .line positionbeing the position of the valve -handle -for .shutting off the supply .of live air, .and the uppermost .dotted line 4`position being the iposition of :the valve/handle in-which the supply of live air is conducted through passageways 5a 'and 5b vprovhied Lin-the back head .4 .and .inthe wall of :the cylinder casting l and opening into the interior .of the .cylinder casting into a groove or annular chamber 5c. This provides-,fa supply lof live air whendesired .to a pointon the interior :of 'the :cylinder casting 1I ladjacent .its forward end `:for ya purpose presently 'to `be described. Suitable valve mechanism which may tbe of con- -ventional .'fdesign, vis .provided Afor causing `the .live air 'to act iiirst iupion one :face Vand then upon the other face -of saidpiston causing 7the piston to'reciprocatewithin'thescylinder. Conventional :means `also :may .be `provided for :causing the piston?) .to :rotate a .fraction .of a revolution each time .it moves :to .its zrearmost position Yafter it has made fa :power stroke, .all .-in a well-known manner. The purpose of this rotation :is to L*rotate the drill Isteelinithe manner hereafter to *be described.

j.Projecting forwardly @from the fhammer piston VY3 is fan Aintegral Apower plunger I `adapted to 'reciprocate within :the bearing bushing' 4 carried in the forward portion :of the `zcylinderr'casting. vThe for-ward Yend ofthis plunger iis Ysplined at `=9 and vadapted to :i-lt slidjngly "within the splined vor rifled interior :of the vrotary `chuck V'rotation Asleeve Vor transmission sleeve Ii Vwhich is `preferably of lbronze orpsom'e other -bearing material softer .than the 4plunger 'I land ithe -cyl- 'inder casting which Yare usually of steel. This sleeve -I0 is mountedwithintheiforward end :of

the cylinder casting `:forrotary but not :forlon- -gitudinal movement. The Y.rotary transmission 'sleeve or Y drive bushing I0 .is :also providedV with -s'hallowsplines on its outerisurface adjacent its -also VAof steel, receives :a `iloearing' bushing J3 of V"bearing metal forming a :bearing Yfor -the rear end of the drill steel shank I4. Locked to rotate with the guide bushing I2 by means of intertting teeth at the forward end of the bushing I2 is an internally splned chuck I5 adapted to receive and force the rotation of the drill steel I6 through interengagement with the laterally projecting lugs I1 on the drill steel. The bushing l2 and chuck I5 are held in place and rotatably mounted within the front head IB.

The front head I8 and the back head 4 are held against the opposite ends of the cylinder in .the .conventional way by means of tie rods I9 engaging with lugs 2li on the back head and lugs 121 on the front head.

vThe .greatestadvantages of the present invention result from Vthe use of the chuck sleeve, rotary drive bushing or transmission sleeve I0 which is shown more in detail in Figs. 3, 4 and 5. The lcylinder casting I is customarily formed of steel or the like, as is also the plunger 'l formed integrally on the forward end of the piston. The vinterior 0f the Cylinder .casting is guarded against wear due to reciprocation of the plunger by means of the bushing 8, and this bushing llkewise serves to form an inner wall for the annular Vlubricant chamber 22 from which lubricantis adapted to flow through thepassages 23 into the bearing between the ,sleeve VIII and the .interior/of the forward end .of the cylinder housing.

The sleeve Il! is lof a material softer than vthe material of the plunger 'I and the cylinder I so astogguard these parts 1 and I against .wear and cause substantially all of the Wear .to take place on the readily replaceable sleeve I0. N0 Specific hardness can be assigned t0 the sleeve Ill' but it should not -be harder than -the cylinder and .plunger surfaces it contacts. rPhe sof-test fina.- terial of which these surfaces would probably be made would be 2,50 g-Brinell, so .that the sleeve In should be `of bearing materiel softer `tlfl r.1-250 ,'-Brinellif it is intended to Ibe used vwith a -cylinder andplungenof minimum hardness,

In 4addition tothe splines providedwithin and upon the sleeve -I vfor engagement with the plunger -'Iv and the sleeve I2 respectively, this sleeve may beprovided on its end surfaces with `grooves 24 and 25 whichserve'as lubricant grooves .during operation of the drill and as passages'for `blowing yair whendrilling is `halted and it is -desired to blow 5air through the drillsteel 4to-clean out the bore hole. Along ,its outer surface the ,sleeve 'I0 is provided with similar vgroves'Z serv.-

ing the Ysaine vpurposes as grooves 24 -and 2 5. Thus .lubricant lfrom the annular chamber 2 2 may be distributed over `the-en tireouter bearing surface of -the `rotary transmission sleeve during operation of the drill, thereby still `further reducing Wear thereon, and when drilling is halted and blowing zis-desired, Vlive air from the chamber 5c ,fmay pass through the grooves 224 and thence be- 'tween'thesplines as Well asthrough the grooves 26, sp1ines I I and grooves t25 yto the space at'the vforward en d of the plunger 'I. Thencejit may pass directly into the rear end ofthe longitudinal :Passage through the drill steel. The grooves 26 surfacefwand V a shoulder provided therefor in the .cylinder castingandits forward end surfaceand a shoulder provided therefor in the sleeve I2. The sleeve I0 will receive rotary movement from the plunger I through the splines 9, and transmit it to the sleeve I2 through the splines lI I. It is further noted that the splined engagement between the rotary transmission sleeve I0 and the sleeve I2 serves to accurately center the sleeve I2 and align it with the sleeve I0. This provides an accurately centered bearing for the shank end of the drill'steel thereby accurately lining it up with the forward end of the plunger I at all times, and resulting in smoother operation.

It is further to be noted that the sleeve I0 can be cheaply and easily made since it has only a cylindrical and two end rotary bearing surfaces and one sliding and one tight splined portion. No threads or the like are necessary.

Furthermore, the sleeve I0 is easily replaceable, it being necessary only to remove the tie rods I9, take off the front head with the chuck, etc., and remove and replace the sleeve I0.

Having described my invention, I claim:

l. In a rock drill, a cylinder having a piston reciprocating and rotating therein formed with a splined plunger, a drill steel to be driven axially and rotated by said plunger, means including a guide bushing for transmitting rotation from said plunger to said drill steel; the improvement which comprises a single rotary transmission sleeve in splined engagement with said plunger to receive rotary movement therefrom and in interlocking engagement with said guide bushing to transmit rotary movement thereto, and in rotary bearing engagement with the interior of the front end portion of said cylinder, said sleeve being of bearing material softer than said plunger and cylinder member.

2. In a rock drill, a cylinder having a piston reciprocating and rotating therein formed with a splined plunger, a drill steel to be driven axially and rotated by said plunger, means including a guide bushing for transmitting rotation for said plunger to said drill steel; the improvement which comprises a single rotary transmission member in sliding splined engagement with said plunger to receive rotary movement therefrom and in splined engagement -with said guide bushing to transmit rotary movement thereto, and in rotary bearing engagement with the interior of the front end portion of said cylinder, said transmission member being of bearing material softer than said plunger and cylinder member.

3. In a rock drill, a cylinder having a piston reciprocating and rotating therein formed with a splined plunger, a drill steel to be driven axially and rotated by said plunger, means including a guide bushing for transmitting rotation from said plunger to said drill steel; the improvement which comprises a single rotary transmission sleeve in sliding splined engagement with the splines on said plunger to receive rotary movement therefrom and in splined engagement with one end portion of said guide bushing to transmit rotary movement thereto, and in rotary bearing engagement with the interior of the front end portion of said cylinder, said sleeve having its surfaces which are in such splined and rotary bearing engagement of bearing material of different hardness than the parts engaged by such surfaces.

4. In a rock drill a cylinder having a piston reciprocating and rotating therein formed with a splined plunger, a drill steel to be driven axially and rotated by said plunger, means including a guide bushing for transmitting rotation from said plunger to said drill steel; the improvement which comprises a single rotary transmission sleeve in splined engagement with said plunger to receive rotary movement therefrom and in splined engagement with said guide bushing to transmit rotary movement thereto, and in rotary bearing engagement with the interior of the front end portions of said cylinder, said sleeve being of bearing material softer than said plunger and cylinder member, and having longitudinal passageways formed therein for conducting blowing air from the rearward to the forward end of the sleeve.

5. As a sub-combination, an integral transmission sleeve for a rock drill, said sleeve having its bo-re splined to receive a splined plunger and receive rotary motion therefrom, thrust bearing surfaces on the op-posite ends of said sleeve, an exterior circumferentially extending bearing surface adapted to provide a bearing for rotary movement of the sleeve, and splines adjacent one end of the sleeve providing a driving connection for transmitting rotary movement from the sleeve, said thrust bearing surfaces having radial blowing air grooves therein and said circumferentially extending bearing surface having longitudinal blowing air grooves therein.

AUGUST H. KATTERJOHN.

' REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,623,411 Hulshizer Apr. 5, 1927 1,668,830 Stevens May 8, 1928 1,700,419 Penberthy Jan. 29, 1929 1,869,595 Katterjohn Aug. 2, 1932 1,968,376 Curtis July 31, 1934 2,049,126 Maybach July 28, 1936 2,108,989 Mack Feb. 22, 1938 2,291,851 Wahlberg et al Aug. 4, 1942 

